<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title> test  focus </title>
	</head>
	<style type="text/css">
		
		/* 当鼠标点击 按下 没有松开的时候，触发 */
		.red-input:focus {
		  background: yellow;
		  color: red;
		  /* outline: 5px solid blue; */
		  outline: none;
		}
		
		.blue-input:focus {
		  background: yellow;
		  color: blue;
		}
		
	</style>
	<body>
		
		<input class="red-input" value="I'll be red when focused."><br>
		<input class="blue-input" value="I'll be blue when focused.">
	</body>
</html>
